The present invention relates to a fishing gear for use on seashore, such as a fishing reel.
In the case of fishing gears such as fishing reels, in order to improve the maneuverability and enhance the strength, their main body portions are generally formed of base metals such as an aluminum alloy and a magnesium alloy so as to realize light weight and high rigidity. In addition, fishing gears are often used near a sea such as on a rocky beach or a boat, and in the case where the main body portion is formed of a base metal as described above, it has been an essential requirement in construction to form an insulating coating on its surface so as to prevent electric corrosion.
Various attached parts are generally attached to the main body portion of the fishing gear, which is constructed as described above, by fixing members such as screws and rivets formed of stainless steel, iron, or brass in association therewith.
As described above, in the case where the main body portion is formed of a base metal, an insulating coating is generally formed on its surface. Since such an insulating coating is formed on the surface of the portion where the fixing member is attached (e.g., the surface of an internally threaded portion), it has been thought that corrosion (electric corrosion) due to the potential difference does not occur between such two members.
However, there are some cases where corrosion occurs between the fixing member and the main body portion. This is attributable to the fact that the insulating coating formed on the surface of the base metal is undesirably peeled off during the operation of attaching the fixing member, and the potential difference can occur due to this cause, resulting in the electric corrosion.
The present inventors conceived of the invention upon finding that the insulating film is likely to be peeled off during such an operation of attaching the fixing member, and that there arises the problem that electric corrosion occurs on the main body member side due to this cause.
Meanwhile, since the fishing gear is frequently used on places where the foothold is unstable, such as a rocky beach and a boat, and the fishing gear is used in environments where it is easily damaged by being dropped by mistake, in order to effectively prevent damage and deformation, a high-strength member in which the surface of a base material formed of a precious metal such as stainless steel, a metal, or a resin is provided with the surface treatment of a precious metal such as chromium plating, nickel plating, or the like is generally used for a damage-prone portion as a protective member (attached part) of the main body member.
Incidentally, when the protective member in which the precious metal is used and the main body portion formed of a base metal are combined (assembled), the potential difference between the two members becomes large, so that electric corrosion occurs. However, the occurrence of such electric corrosion is prevented by means of an insulating coating formed on the aforementioned base metal surface or by separately interposing an insulating member between them.
Nevertheless, despite the above-described electric corrosion preventing structure, the present situation is such that, depending on handling, electric corrosion can occur even in the fishing gear in which the two members are combined (assembled).
The invention has been devised by focusing on such problems, and its object is to provide an arrangement for effectively preventing electric corrosion in the fishing gear in which a member (also referred to as an attached part) formed of a precious metal is assembled onto a member (also referred to as a main body member) formed of a base metal.
The object of the invention is to provide an arrangement for effectively preventing electric corrosion on the main body member side in the fishing gear in which an attached part is attached to a main body member formed of a base metal, by using a fixing member such as a screw.
Another object is to provide an arrangement for effectively preventing electric corrosion in the fishing gear in which a member (also referred to as an attached part) formed of a precious metal is assembled onto a member (also referred to as a main body member) formed of a base metal.
To solve the above-described problems, in accordance with the invention there is provided a fishing gear in which an attached part is assembled onto a main body member formed of a base metal protected by an insulating coating, characterized in that a fixing member for attaching and fixing the attached part to the main body member is formed of an aluminum alloy in which an Fe component is 0.6 wt. % or less, a Cu component is 0.2 wt. % or less, an Ni component is 0.1 wt. % or less, and a Ti component is 0.03 wt. % or less.
As the fixing member is formed of an aluminum alloy which is a base metal, even if the insulating coating of the main body member formed of a base metal is peeled off, the potential difference between the main body member and the fixing member is small, so that it is possible to suppress electric corrosion of the main body member. In this case, however, if components of iron, copper, nickel, titanium, and the like, which are components added as the aluminum alloy, increase, the tendency of occurrence of electric corrosion between the alloy components and the base metal of the main body member becomes strong. Therefore, the weight percentage of the respective added components mentioned above is at least set within the above-described ranges. It should be noted that not all the aforementioned added components may be included, and the percentage of some components may be 0 wt. %.
The inventors surmised that the cause of occurrence of electric corrosion lies in the fixing member such as a screw or a rivet which is used when the attached part formed of a precious metal is assembled to the main body member formed of a base metal, and conducted the following test.
A main body member (here a rotor portion of the fishing reel) was formed of a base metal coated with an insulating coating on its surface, and an attached part provided with surface treatment with a precious metal was attached to it by means of a fixing member (screw) made of stainless steel, iron, brass, or the like, which is generally used. In this case, an internally threaded portion was formed in the main body member, and an insulating coating was formed on the surface of this internally threaded portion as well. Then, scorings and pinholes were provided in advance at arbitrary portions of the main body member, and when a saline-water spraying test was performed, the results obtained were such that corrosion advanced appreciably in the scored portions and the pinhole portions in a period of about 20 days.
As the cause for the appreciable advance of such corrosion, it is conceivable that in a case where the fixing member for fixing the two members is formed of a precious metal, at the time of the usually performed operation of attaching the fixing member, the insulating coating formed on the surface of the internally threaded portion is peeled off, with the result that the fixing member and the base metal member (main body member) are electrically connected, thereby forming a circuit through which electrons flow. Namely, once the insulating coating is peeled off, saline water becomes attached to the aforementioned pinhole portions and scored portions and to the fixing member, thereby undesirably forming a circuit through which electrons flow in the route including: xe2x80x9csaline waterxe2x80x94pinhole (score) xe2x80x94base metalxe2x80x94fixing memberxe2x80x94saline water.xe2x80x9d Moreover, since the flow of electrons occurs constantly, the advance of corrosion does not stop, causing the occurrence of large electric corrosion in the pinhole portions and the scored portions.
On considering that the above-described drawback could be overcome by forming the fixing member of a base metal, the fixing member was replaced with one made of a base metal, and the aforementioned test was performed again, but the results were such that electric corrosion still occurred.
This is conceivably attributable to the fact that at the time of the operation of attaching the base metal-made fixing member for assembling the precious metal-made attached part onto the main body member, the insulating coating formed on the surface of the internally threaded portion of the main body member is peeled off in the same way as described above, and that the fixing member electrically connects the attached part surface-treated with a precious metal and the main body member, thereby producing a potential difference. As such, if saline water is attached to the attached part as well as the pinhole portions and the scored portions, a circuit through which electrons flow is undesirably formed in the route including: xe2x80x9csaline waterxe2x80x94pinhole (score)xe2x80x94base metalxe2x80x94fixing member xe2x80x94saline water.xe2x80x9d Consequently, in the same way as described above, large electric corrosion conceivably occurs in the pinhole portions and the scored portions.
Accordingly, on the basis of the results of the above-described tests, the inventors prepared test pieces in each of which the attached part was fixed to the main body member by using the screw (fixing member) formed of a base metal-base material, and an insulating member was interposed between the screw and the attached part, and conducted a similar saline-water spraying test was performed. Then, the results were obtained in that advance of electric corrosion was not observed in the pinhole portions.
On the basis of the details discovered through the above-described tests, the inventors provide a fishing gear in which electric corrosion is difficult to occur by providing an arrangement such that when the attached part formed of a precious metal is assembled by a fixing member onto the main body portion formed of a base metal protected by an insulating coating, the circuit through which electrons flow is not formed even if the insulating coating is peeled off.
Namely, in accordance with the invention there is provided a fishing gear in which an attached part formed of a precious metal is assembled onto a main body member formed of a base metal protected by an insulating coating, characterized in that a fixing member for attaching and fixing the attached part to the main body member is formed of abase metal, and an insulating portion for insulating electrical conduction is provided between the fixing member and the attached part.